This invention relates to a system for determining the service life of an image bearing member or a magazine containing an image bearing member of a copying apparatus and the like.
Heretofore, it has been usual practice to determine the service life of an image bearing member or a photosensitive member of a copying apparatus based on the number of times the photosensitive member is rendered operative as indicated by a counter attached to a main body of the copying apparatus and to replace the old photosensitive member by a new one by a service clerk when a predetermined number of times is reached.
Copying apparatus have nowadays become very popular and are used widely not only in business offices but also for personal use at home. It has become necessary to reduce expenses for servicing the machines by letting the users perform replacements of photosensitive members themselves without requiring servicing by a service clerk. When the users are required to take care of the photosensitive members, the system of determining the service life of a photosensitive member now in use which relies on the operation of a counter to count and indicate the number of times it is rendered operative would suffer disadvantages. If the system is of a type in which the counter is not resettable, the users might forget to keep a record of the number of times the counter indicated at the time the replacements took place the last time. Even if the counter used is resettable, the users might forget to reset the counter. Also, when an old photosensitive member that has reached the end of its service life and replaced by a new one or a magazine containing the old photosensitive member is put in an empty box that used to contain the new photosensitive member or magazine that has replaced the old one, there would be the risk that the photosensitive member or magazine in the box might be mistaken for a new one and inadvertently mounted on the copying apparatus, resulting in the production of copies of poor quality.
To obviate this problem, proposals have been made to provide each of the replaceable kits including a photosensitive member with means for determining the service life, to enable the users to learn the service life of the kit in use, as disclosed in Japanese Patent Application Laid-Open No. 57-163276 for example. When this solution of the problem is adopted, the users would be able not only to determine when the kit now in use would reach the end of its service life but also to learn that the used kit has reached the end of its service life.
However, this solution of the problem is not without disadvantages. The kits are disposable and it would cause a rise in cost to provide each of them with means for determining the service life.